The present invention relates generally to data communications. More particularly, the present invention relates to a data link layer switch with protection against Internet Protocol spoofing.
Secure data communications networks such as corporate intranets are the subject of increasingly numerous and sophisticated attacks from outside the network. One common component of such attacks, referred to as Internet Protocol (IP) spoofing, alters the IP source address of packets transmitted by the attacker. One purpose of IP spoofing is to conceal the identity of the attacker.
Another purpose of IP spoofing is to present the attacker as a user within the secure intranet under attack. Because devices within a secure intranet trust each other, an attacker masquerading as such a device can do more damage than an attacker that appears to be outside the network. For example, an attacker could transmit packets to a local-area network (LAN) using a altered or “spoofed” address of 192.168.1.200. Because this is the form of the internal IP addresses for many small LANs, the attacker may be accepted as a computer within the LAN.